Concerning the 'Wanzlick equilibrium'

Tetrahedron Letters

Volumn 41, Issue 5, 2000, Pages 599-602

  Liu, Yufa ^a   Lemal, David M ^a  

^a Lamont Doherty Earth Observatory   (United States)

Author keywords

Carbenes; Catalysis; Equilibrium; Exchange reactions

Indexed keywords

CARBENE; ETHYLENE DERIVATIVE;

ARTICLE; CATALYSIS; EQUILIBRIUM CONSTANT; REACTION ANALYSIS; SYNTHESIS;

EID: 0034728193     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(99)02161-9     Document Type: Article

References (25)

1. Wanzlick, H.-W.; Schikora, E. Angew. Chem. 1960, 72, 494.
2. For reviews of this work, see: Hoffmann, R. Angew. Chem., Int. Ed. Engl. 1968, 7, 754; Wiberg, N. Angew. Chem., Int. Ed. Engl. 1968, 7, 766. Lemal, D. M. In The Chemistry of the Amino Group; Patai, S., Ed.; Interscience: New York, 1968; p.701.
3. For reviews of this work, see: Hoffmann, R. Angew. Chem., Int. Ed. Engl. 1968, 7, 754; Wiberg, N. Angew. Chem., Int. Ed. Engl. 1968, 7, 766. Lemal, D. M. In The Chemistry of the Amino Group; Patai, S., Ed.; Interscience: New York, 1968; p.701.
4. For reviews of this work, see: Hoffmann, R. Angew. Chem., Int. Ed. Engl. 1968, 7, 754; Wiberg, N. Angew. Chem., Int. Ed. Engl. 1968, 7, 766. Lemal, D. M. In The Chemistry of the Amino Group; Patai, S., Ed.; Interscience: New York, 1968; p.701.
5. Lemal, D. M.; Lovald, R. A.; Kawano, K. I. J. Am. Chem. Soc. 1964, 86, 2518.
6. Winberg, H. E.; Carnahan, J. E.; Coffman, D. D. J. Am. Chem. Soc. 1965, 87, 2055.
7. Arduengo III, A. J.; Harlow, R. L.; Kline, M. J. Am. Chem. Soc. 1991, 113, 361.
8. For recent reviews on tetraaminoethylenes and diaminocarbenes, see: Arduengo III, A. J.; Krafczyk, R. Chemie in unserer Zeit 1998, 32, 6; Warkentin, J. In Advances in Carbene Chemistry; Brinker, U. H., Ed.; Jai Press: London, 1998; Vol. 2, p. 245; Herrmann, W. A.; Köcher, C. Angew. Chem., Int. Ed. Engl. 1997, 36, 2162; Regitz, M. Angew. Chem., Int. Ed. Engl. 1996, 35, 725.
9. For recent reviews on tetraaminoethylenes and diaminocarbenes, see: Arduengo III, A. J.; Krafczyk, R. Chemie in unserer Zeit 1998, 32, 6; Warkentin, J. In Advances in Carbene Chemistry; Brinker, U. H., Ed.; Jai Press: London, 1998; Vol. 2, p. 245; Herrmann, W. A.; Köcher, C. Angew. Chem., Int. Ed. Engl. 1997, 36, 2162; Regitz, M. Angew. Chem., Int. Ed. Engl. 1996, 35, 725.
10. For recent reviews on tetraaminoethylenes and diaminocarbenes, see: Arduengo III, A. J.; Krafczyk, R. Chemie in unserer Zeit 1998, 32, 6; Warkentin, J. In Advances in Carbene Chemistry; Brinker, U. H., Ed.; Jai Press: London, 1998; Vol. 2, p. 245; Herrmann, W. A.; Köcher, C. Angew. Chem., Int. Ed. Engl. 1997, 36, 2162; Regitz, M. Angew. Chem., Int. Ed. Engl. 1996, 35, 725.
11. For recent reviews on tetraaminoethylenes and diaminocarbenes, see: Arduengo III, A. J.; Krafczyk, R. Chemie in unserer Zeit 1998, 32, 6; Warkentin, J. In Advances in Carbene Chemistry; Brinker, U. H., Ed.; Jai Press: London, 1998; Vol. 2, p. 245; Herrmann, W. A.; Köcher, C. Angew. Chem., Int. Ed. Engl. 1997, 36, 2162; Regitz, M. Angew. Chem., Int. Ed. Engl. 1996, 35, 725.
12. Denk, M. K.; Hatano, K.; Ma, M. Tetrahedron Lett. 1999, 40, 2057.
13. While these peaks are easily resolved with a high field NMR instrument, it was necessary in the original work to oxidize the dimers to their dications in order to resolve all four methylene signals at 60 MHz.
14. Other kinds of catalysis are conceivable, e.g. free radical or oxidative. The latter deserves consideration because of the ease of oxidation of 1 and 3 to their radical cations and dications. Lemal, D. M.; Kawano, K. I. J. Am. Chem. Soc. 1962, 84, 1761.
15. Potassium hydride has been used to prevent the acid-catalyzed dissociation of a bis(thiazol-2-ylidene). Arduengo III, A. J.; Goerlich, J. R.; Marshall, W. J. Liebigs Ann./Recueil 1997, 365. Recently it has been found to inhibit strongly the adventitiously catalyzed dissociation equilibrium of a bis(benzimidazol-2-ylidene). Liu, Y.; Lindner, P. E.; Lemal, D. M. J. Am. Chem. Soc., 1999, 121, 10626.
16. Potassium hydride has been used to prevent the acid-catalyzed dissociation of a bis(thiazol-2-ylidene). Arduengo III, A. J.; Goerlich, J. R.; Marshall, W. J. Liebigs Ann./Recueil 1997, 365. Recently it has been found to inhibit strongly the adventitiously catalyzed dissociation equilibrium of a bis(benzimidazol-2-ylidene). Liu, Y.; Lindner, P. E.; Lemal, D. M. J. Am. Chem. Soc., 1999, 121, 10626.
17. The hydride had no influence on the tetraaminoethylene NMR spectra.
18. Again no 4 could be detected when the experiment was carried out at 160°C for 5.5 h, but there was considerable loss of starting material at this temperature.
19. The supernatant from this sample was transferred to a new NMR tube and heated for another 5 h at 140°C, with no change. Then a very small amount of N,N′-diphenylimidazolinium chloride was added as a potential electrophilic catalyst (albeit a highly insoluble one). Heating was resumed at the same temperature, and within one hour a substantial amount of the crossover product 4 had formed.
20. For theoretical comparisons between the N-unsubstituted analogs of 2 and 5, see: Heinemann, C.; Thiel, W. Chem. Phys. Lett. 1994, 217, 11; Heinemann, C.; Müller, T.; Apeloig, Y.; Schwarz, H. J. Am. Chem. Soc. 1996, 118, 2023; Boehme, C.; Frenking, G. J. Am. Chem. Soc. 1996, 118, 2039.
21. For theoretical comparisons between the N-unsubstituted analogs of 2 and 5, see: Heinemann, C.; Thiel, W. Chem. Phys. Lett. 1994, 217, 11; Heinemann, C.; Müller, T.; Apeloig, Y.; Schwarz, H. J. Am. Chem. Soc. 1996, 118, 2023; Boehme, C.; Frenking, G. J. Am. Chem. Soc. 1996, 118, 2039.
22. For theoretical comparisons between the N-unsubstituted analogs of 2 and 5, see: Heinemann, C.; Thiel, W. Chem. Phys. Lett. 1994, 217, 11; Heinemann, C.; Müller, T.; Apeloig, Y.; Schwarz, H. J. Am. Chem. Soc. 1996, 118, 2023; Boehme, C.; Frenking, G. J. Am. Chem. Soc. 1996, 118, 2039.
23. Alder, R. W.; Blake, M. E. J. Chem. Soc., Chem. Commun. 1997, 1513.
24. Alder, R. W.; Blake, M. E.; Bortolotti, C.; Bufali, S.; Butts, C. P.; Linehan, E.; Oliva, J. M.; Orpen, A. G.; Quayle, M. J. J. Chem. Soc., Chem. Commun. 1999, 241.
25. Wanzlick, H.-W. Org. Synth. Coll. Vol. 5, 1973, 115.